UITextView占位符

self.textView.delegate = self;
>>//开始编辑

- (void)textViewDidBeginEditing:(UITextView *)textView {
    if ([self.textView.text isEqualToString:@""]) {
        textView.text = @"";
        self.textView.textColor = [UIColor blackColor];
    }
}
//在结束编辑的代理方法中进行如下操作
- (void)textViewDidEndEditing:(UITextView *)textView {
    if (textView.text.length<1) {
        self.textView.text = @"";
        self.textView.textColor = colorText;
    }
}